In this study, we investigated the cervical enamel projection (CEP) and intermediate bifurcational ridge (IBR) correlated with localized molar furcation involvement (FI). Study samples consisting of 87 hopeless permanent mandibulars (56 first and 31 second molars), which required extraction for periodontal therapy, were randomly collected from the School's Dental Clinic. The furcal defects, CEPs, and IBRs of molars were diagnosed via clinical probing, periapical radiographs, and inspection of ground tooth sections of extracted teeth with a stereomicroscope. Prevalence and distribution of molars with CEPs and/or IBRs were also analyzed. Probing depths (PD), clinical attachment loss (CAL), gingival index (GI), and plaque index (PLI) were measured for the buccal and lingual surfaces of molar furcal areas. Moreover, the relationships between the molar FI with and without CEPs and IBRs and periodontal status were analyzed using Student's paired t-test. Based on those results, we can conclude the following: 1) among 87 molars with FIs examined, 63.2% (55/87) had cervical enamel projections and bifurcational ridges, and the prevalence was greatest in mandibular first (67.9%, 38/56) and second (54.8%, 17/31) molars; and 2) the differences in mean PD, CAL, PLI, and GI between the molars with and without CEPs and IBRs were highly significant (P < 0.001) in the mandibular first and second molars.